Chaparral habitat in the city has been grouped into two categories: undifferentiated (including southern mixed and chamise chaparral) and southern maritime chaparral.
Southern mixed and chamise chaparral
Southern mixed chaparral is a fire- and drought-adapted plant community composed of a variety of woody shrubs, many of which are "stump sprouters" that regenerate rapidly from undamaged underground tissues following fires or other ecological perturbations. The dominant shrubs vary from site to site. In most situations the dominants include chamise, Nuttall's scrub oak, mission manzanita, laurel sumac, lemonadeberry, and toyon. Understory plants may include rush-rose, deerweed, wreathplant, and a variety of aster and daisy relatives.
Chamise chaparral is a community dominated by chamise, which may comprise up to 90 percent of the relative cover. The remaining species include shrubs and understory plants common in other types of chaparral.
These chaparral types have a patchy distribution throughout Carlsbad, occurring on wetter north- and west-facing slopes, alternating with coastal sage scrub, grasslands, and oak woodlands.
Southern maritime chaparral
Southern maritime chaparral is similar to southern mixed chaparral, but occurs on sandstone. It is the most limited type of chaparral in Carlsbad, and is characterized by several endemic shrubs, including Del Mar manzanita, wart-stemmed ceanothus, coast spice bush, and Nuttall's scrub oak. Summer holly is also associated with this habitat type. Other dominant shrubs are the same as those listed for the other two types of chaparral. Southern maritime chaparral is considered a sensitive habitat.